1. Field of the Invention
This invention relates generally to electric storage battery chargers, testers, and methods of operation therefor and, more particularly, to a combined charger and tester for an electric storage battery and a method of operation therefor implementing multiple tests to determine battery condition prior to, during, and after battery charging.
2. Discussion of the Related Art
As is well understood in the art, a vehicle includes an electric storage battery that provides the power necessary to start the vehicle and to operate the various vehicle systems. The vehicle also includes an alternator that charges the battery when the vehicle is running so that the battery maintains a sufficient charge for these purposes. A typical vehicle battery will be a 12 volt lead-acid battery including six independent cells electrically connected together. Other sized batteries may also be used for this purpose, such as 6 volt batteries having three independent cells. Each cell in a battery of this type includes a positive and negative terminal, and the cells are electrically connected together in a series configuration.
Due to various reasons, such as a power drain on the battery when the vehicle is not running, the capacity of a vehicle battery may become diminished, and the battery will not be able to provide the power necessary to start the vehicle and/or operate the various vehicle systems. It is therefore necessary to use a separate charging device to recharge the battery and return it to its full or near full capacity for subsequent use in the vehicle. It has heretofore been known to be desirable to test the battery prior to recharging it to ensure that one or more cells in the battery are not defective, making recharging of the battery useless and unwise. Charging a battery having one or more bad cells may provide certain health and safety risks in that the bad cell may emit harmful smoke and/or gases during the charging sequence.
To facilitate such testing, there are a variety of known battery testers including light load testers, heavy load testers, and conductance testers, each having their own advantages and disadvantages. The light and heavy load testers typically connect a resistive load to the battery for a period of time in order to draw a relatively light or heavy battery current, respectively. Unlike load testers, conductance testers are passive in that they do not draw any appreciable current from a battery under test. Thus, conductance testers are more effective than traditional load testers in analyzing batteries at a low state of charge. However, there are times when it is desirable to draw battery current during testing, so load testers still have use. Traditionally, batteries have been analyzed with a single type of test prior to charging the battery.
Much like a physician who prefers to evaluate a patient using not simply one, but a number of tests offering different perspectives on the patient's condition, what is needed in the context of battery testing and charging is a technique for evaluating multiple tests providing distinct insights into battery condition before, during, and after battery charging. It is therefore an object of the present invention to provide such a technique.